Abstract
This narrative review will summarise a clinical approach to the investigation of back pain in children and adolescent patients, including a discussion of the epidemiology, presentation, investigation and clinical management of back pain in children and adolescents. This will assist the prompt and accurate diagnosis of spinal disorders that require significant medical intervention. Existing evidence suggests a relatively high incidence of non-specific back pain among young people; 27–48% of presentations of back pain in children and adolescents are attributed to non-specific back pain. Low back pain among schoolchildren is often linked to psychosocial factors and only occasionally requires medical attention, as pain is benign and self-limiting. Nonetheless, those young patients who seek medical assistance exhibit a higher incidence of organic conditions underlying the major symptom of spinal pain. A cautious and comprehensive strategy – including a detailed history, examination, radiographic imaging and diagnostic laboratory studies – should be employed, which must be accurate, reliable, consistent and reproducible in identifying spinal pathologies. A specific diagnosis can be reached in 52–73% of the cases. For cases in which a specific diagnosis cannot be made, re-evaluation after a period of observation is recommended. At this later stage, minor symptoms unrelated to underlying pathology will resolve spontaneously, whereas serious pathologies will advance and become easily identified.
Introduction
Back pain is experienced by 10–30% of the normal young population by their teenage years [1]. While back pain related to benign and malignant tumours is relatively rare in children and adolescents, it is often misunderstood and mismanaged. This narrative review will summarise a clinical approach to the investigation of back pain in children and adolescent patients, including a discussion of the epidemiology, presentation, investigation and clinical management of back pain in children and adolescents. The process for selection of articles in this narrative review is described in the Appendix.
Differential diagnosis of back pain in children and adolescents
Differential diagnosis of back pain in children and adolescents
Recent studies suggest that non-specific lower back pain among schoolchildren is far more common than previously believed and may not be associated with significant underlying pathology [2, 3, 4, 5, 6, 7]. The incidence of childhood back pain increases with age, rising to around 25% during adolescence [8, 9, 10]. There is a very low prevalence of 1% among 7-year-olds [2], rising to 6% among 10-year-olds, 12% among 12-year-olds, and 18% among adolescents aged 14–16 years. Among older children, Burton et al. [11] reported that the annual incidence of low back pain increased from 12% among 12-year-olds to 22% among 15-year-olds, and also that it has a recurrent nature. Various studies support the suggestion that the incidence of back pain is greatest between the ages of 13–15 years old, reporting a varying incidence of 11.5%, 26% and 33% [12].
At this young age, back pain neither deteriorates progressively nor does it cause the significant morbidity observed among adults with chronic lower back pain. Among children with back pain, 30% report a reduction in physical activity and sporting performance, and 25% report absence from school [13]. Increasingly, evidence suggests that childhood and adolescent back pain is predictive of adulthood lower back pain [14, 15, 16, 17, 18]. Higher levels of back pain are reported by adolescents with degenerative disc changes present in MRI [16]. At the age of 15 years, lumbar disc degeneration is predictive of back pain in the following three years, and persistent recurrent back pain in adulthood [12]. While low back pain among children and adolescents is typically benign and self-limiting, Cardon and Balague [19] showed in a literature review that psychosocial disturbance is often associated with back pain reported by schoolchildren.
Despite this prevalence, only 2% of all referrals to a paediatric orthopaedic service involve children presenting with back pain [20]. Among 13–15 year olds suffering from back pain, approximately 15.6% seek medical assistance, with no evidence suggesting predominance based on gender [2, 21]. This contrasts sharply with the situation for back pain in adulthood, with a reported incidence of 60–80% and two-thirds of patients experiencing recurrences [12].
In most cases, evaluation of the spine in children and adolescents is instigated following the development of spinal pain, the discovery or suspicion of spine deformity, or the identification of asymptomatic spinal abnormalities during unrelated imaging examinations (such as the discovery of congenital vertebral anomaly – often isolated hemivertebra – on a chest radiograph in course of cardiac or pulmonary assessment). However, many children dismiss the development of recurrent back symptoms as unremarkable and fail to seek medical assistance, causing significant delays to diagnosis and treatment. Persistent back pain in children and adolescents is commonly associated with serious pathology. These delays may – under some conditions – impact negatively on prognosis, treatment decisions and the effectiveness of available interventions, in addition to extending patient morbidity.
While mild to moderate discomfort may be benign, physicians should always aim to identify any underlying source of symptomatology through detailed evaluation. Table 1 outlines the various disorders, which can generate severe back pain during childhood and adolescence. Further risk factors include increasing age, female gender, increased height, family history of back pain, increased physical activity, psychological disorders, smoking, and carrying heavy loads [3, 22, 23, 24, 25, 26]. The strategy for assessing the spine in paediatric patients should be accurate, reliable and easily reproducible in the identification of potential spinal pathology, involving a detailed history, physical examination, radiographic imaging and appropriate diagnostic laboratory studies.
The most efficient method of initial screening examination remains the use of plain radiographs. The supplementary use of single photon emission computed tomography (SPECT) is successful in identifying a pathological condition in only 22% of patients, according to Ryoppy et al. [27]. It is always valuable to re-assess a child after initial observation for cases in which an exact diagnosis cannot be determined. Ongoing monitoring and later reassessment may allow minor symptoms (unrelated to any underlying pathology) to resolve spontaneously, and serious pathology to be determined.
Previous studies suggest the likelihood of identifying the underlying cause of spinal pain to be 52–73% [20, 28]. Spondylolisthesis and Scheuermann’s kyphosis are the most common diagnoses [20, 29, 30, 31], but tumours are found in 6–11% of children with spinal pain [20, 29, 30, 31]. Clinicians must therefore interpret very seriously the presentation of childhood and adolescent back pain, conducting detailed clinical examination and initiating appropriate further investigations.
The clinician should be informed by a comprehensive and detailed history in determining whether and how to investigate further children and adolescents presenting with back pain. To improve the accuracy and completeness of information provided to the clinician, a parent should accompany all children and adolescents at their visit to the clinic. This is particularly critical for children aged 5 years and below, whose communication skills are still developing and whose pain localisation may be less precise.
Mechanical and non-mechanical sources of spinal pain should be differentiated by the physician. While mechanical pain is aggravated by physical activity and alleviated by rest or change in body position, non-mechanical pain is less variable and unchanged by physical activity.
To determine the context of the onset and duration of symptoms, was there a history of preceding trauma or infection? A recent urinary tract infection or an otitis media might suggest an infectious condition (e.g. discitis or vertebral osteomyelitis). Recent foreign travel or an episode of trauma may suggest exposure to atypical infections (e.g. tuberculosis). Constitutional symptoms including high temperature, lethargy, malaise, pallor, anorexia, weight loss, bowel or bladder changes may suggest systemic illness, or malignant or infectious aetiology. It is noteworthy that 6% of children with acute lymphocytic leukaemia complain of back pain. In young females, gynaecological disorders – especially pelvic inflammatory disease and ovarian pathology – can be associated with back pain. It is therefore valuable to establish menstrual history and any abnormal symptoms such as vaginal discharge.
To establish the onset of symptoms, did the pain appear acutely or was there a gradual onset? And for how long did the pain symptoms persist? Mild pain present for a short period after intense athletic activity may be attributed to muscle sprain or overuse. By contrast, spinal pain which has persisted over weeks or months without improvement suggests the need for further investigation. Which factors cause or worsen the pain (e.g. specific physical activities)? To take two examples, spondylolysis and spondylolisthesis often occur in children playing sports that require repetitive hyperextension of the spine, such as gymnastics (backhand springs and walk-overs), football, swimming (especially butterfly stroke) or dance.
A full history of the child’s symptomatology will include an understanding of the location, radiation, severity, frequency and nature of the back pain. Back pain such as spondylolysis/spondylolisthesis or spinal neoplasms can be located to a specific area of the spine. In an infant, discitis or spinal neoplasm may manifest as discomfort when lying supine, and may be relieved by suspension when lifted from beneath the arms. In adolescents, generalised thoracic discomfort is commonly observed in the presence of Scheuermann’s kyphosis.
Disc herniation or a space-occupying intraspinal lesion may be indicated by radiation of the pain to the buttocks with or without associated neurological findings (such as numbness, tingling or muscle weakness). Spinal cord pathology (including spinal dysraphism or neoplasm) may be related to the presence of neurological abnormalities such as bowel or bladder incontinence, loss of balance or coordination, and change in the gait. Mild changes in gait or loss of previous motor skills suggest subtle neurologic changes.
In cases of a tumour, infection or inflammatory condition involving the vertebral column of the spinal cord, the initial complaint may be persistent night pain (which is unrelated to physical activity and unresponsive to rest). Early morning pain or stiffness (after relative inactivity) may suggest an inflammatory condition. An osteoid osteoma is suggested if the use of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) leads to the immediate relief of pain (including night pain). Patients may have juvenile rheumatoid pain or ankylosing spondylitis if back pain and other joint symptoms are relieved by NSAIDs.
A patient (A) presented with severe thoracic scoliosis and thoracolumbar hairy patch. (B) MRI of the spine demonstrated an extensive cervical syrinx.
The impact of symptoms on the normal activities of the child should be one of the most significant factors in determining the severity of reported spine pain and the need for further investigation. If the reported pain has led to a reduction or cessation of normal play or physical activities, it must be considered genuine and evaluated thoroughly. Additional helpful information could include the child’s hobbies, participation in school and sport, and the nature and weight of any school bag.
Patient history should also include previous medical or surgical events, fractures or illnesses, regular medication and drug allergies. Family history may also indicate conditions with a familial pattern of inheritance, including idiopathic scoliosis, disc herniations, and inflammatory joint or hereditary neurological conditions.
The social history of a child’s developmental environment may also have implications for symptomatology. Although at a much lower prevalence than in the adult population, psychological causes of back pain exist among children. Unassociated sources of pain such as recurrent headaches and abdominal discomfort are often reported by children complaining of spinal pain. Also, children may mimic the symptoms of parents, siblings, grandparents or friends. Therefore, the potential connection between these symptoms and underlying psychosocial problems should always be investigated when a meticulous evaluation fails to identify a specific cause of spinal pain. Conversion and psychosomatic conditions are a diagnosis of exclusion, but merit consideration.
Age of the child may also help to differentiate between potential conditions. For children aged under 10 years, the most frequent causes of back pain are infection (particularly discitis) and tumour. For those children aged over 10 years, more benign conditions such as overuse syndrome, spondylolysis, spondylolisthesis and Scheuermann’s kyphosis are most common. Young children are generally unlikely to exaggerate any symptoms.
Children and adolescents also occasionally develop inflammatory conditions, such as juvenile ankylosing spondylitis. There may be complaints of vague spinal pain, symptoms in other joints (often the hips), and wider systemic manifestations including stiffness, fatigue and decreased stamina.
Physical examination of the patients should commence with a general examination involving measurement of pulse and temperature, and screening for any signs of infection or malignancy including lymphadenopathy, abdominal masses, skin lesions, muscle spasm, or muscle wasting. Skeletal screening should then be undertaken to examine the patient’s gait, head, neck, upper and lower extremities, and trunk for any asymmetry. Torticollis may indicate a primary orthopaedic condition or represent an underlying neurological condition. The assessment for spinal asymmetry should include assessing the coronal and sagittal planes of the trunk, imbalance of the shoulders, prominence of the scapulae, translocation and decompensation of the thorax, asymmetry of the waist, obliquity of the pelvis, and any leg length discrepancy. Spinal dysraphism may be suggested by the finding of any abnormalities of the skin or subcutaneous tissues overlying the affected region of the spine, which may include midline defects, hairy patches, sinuses, lipomas, dimples, or haemangiomas (Fig. 1). An underlying diagnosis of neurofibromatosis may be indicated by the presence of cutaneous abnormalities such as café au lait lesions. Tenderness to palpation of the posterior spinal bony elements or sacroiliac joints may indicate a traumatic, neoplastic, or infective pathology.
Plain lateral radiograph (A), axial and sagittal MRI scans (B and C), which show stenosis of the intervertebral disc space with erosion of the adjacent superior and inferior end plates and the L1 vertebral body in a patient with L1-L2 tuberculous spondylodiscitis.
Alignment and flexibility of the thoracic and lumbar spine can be assessed by Adam’s forward bending test. Identification of a scoliotic deformity should be assessed further to determine if the deformity is structural (fixed) or non-structural (correctable). If the deformity is fixed, then the scoliosis does not correct with changes in the patient’s posture, whereas if the curve is non-structural, it will disappear upon postural changes such as forward bending, sitting or on suspension of the patient. The presence of both trunk asymmetry (demonstrated on the forward bending test) and deviation of the trunk to one side (trunk translation) indicates asymmetric spinal muscle spasm that may be due to neoplasms, infections, spinal cord abnormalities, a herniated disc, spondylolysis, or spondylolisthesis. In addition to muscle spasm, the physician should also examine for any restriction of spinal mobility. Forward flexion can be assessed by Schober’s test. Reduced or restricted movements of the lumbar spine may indicate disc herniation, inflammatory spondylitis, spondylodiscitis, or neoplasm. Lumbosacral pain associated with a reduction of the normal lumbar lordosis and hamstring tightness is suggestive of spondylolysis or spondylolisthesis. The gait pattern of the patient must also be assessed, including an examination for signs of ataxia, muscle atrophy, and whether or not the patient can toe walk and heel walk.
Plain AP radiograph (A) of a patient who presented with lumbar and right leg pain shows absence of the right L3 pedicle with increased radionuclide uptake on the bone scan (B). Further CT imaging with 3D reconstruction (C and D) and MRI (E) demonstrated an expansile lesion with a soap bubble appearance and delineated the anatomy of the tumerous lesion (aneurysmal bone cyst), which involved the right pedicle, lamina, and the posterolateral aspect of the vertebral body extending into the right foramen and causing nerve irritation and radicular symptoms.
Plain radiograph (A) of a patient who presented with complaints of localised mid-thoracic pain shows segmental absence of the spinous process. MRI scan (B) illustrated the presence of a unicameral bone cyst involving the spinous process and extending into the laminae, which caused pain due to the development of a pathological fracture of the anterior cortex.
Plain AP radiograph (A) of a patient with a right thoracolumbar scoliosis and evidence of widening of the interpedicular distance at the T6 level. Further investigation with MRI indicated the presence of a syringomyelia (B), and a diastematomyelia bony spur (C).
Lateral radiographs of the spine in flexion-extension (A and B) show evidence of instability at the L2-L3 level in a patient who presented with lumbar pain following a road traffic accident. A posterior spinal fusion with the use of instrumentation and locally harvested bone autograft restored stability at the affected spinal segment as illustrated in the repeat postoperative flexion-extension views (C and E).
Axial and sagittal CT scan (A and B) of a patient who presented with complaints of persistent back pain, which was worse at night shows an osteolytic lesion (osteoid osteoma) of the articular facet. Note the increased uptake on the Tc 99 m bone scan (C).
A patient with congenital cervicothoracic scoliosis (A) and tethered cord at the level of L3 (B). Following a detethering procedure the scoliosis was corrected with posterior instrumentation (C).
A comprehensive neurological examination should comprise motor and sensory testing, reflex testing of upper and lower extremities, assessment for any asymmetry of the lower limbs (unilateral muscular atrophy), and evaluation for deformities of the feet (neuropathic foot). Abnormalities of the limb reflexes will indicate if the pathology is located in the central or peripheral nervous system. The presence of pathological plantar reflexes or clonus represents central nervous pathology. Asymmetry of the abdominal reflexes may be the only clinical manifestation of intraspinal anomalies, such as syringomyelia or a spinal cord tumour. Straight leg raising and crossed straight leg raising should be checked to investigate for any evidence of radiculopathy or nerve tension signs.
Imaging studies are indicated in the further investigation of children and adolescent patients whose back pain does not resolve with conservative management, such as analgesia or physiotherapy, or if a patient’s symptoms deteriorate, or if there is concern regarding underlying pathology. Plain spinal radiography is the most appropriate initial imaging modality. Paediatric patients with back pain should initially have a postero-anterior (PA) and lateral radiograph of the spine focused on the region of greatest discomfort. Disc narrowing, irregularity of the vertebral end plates, Schmorl nodes, destructive-radiolucent or radiodense lesions, vertebral scalloping, congenital vertebral anomalies, evidence of a fracture or a pars interarticularis defect, and osteopenia are some of the abnormal findings that may be detected on plain radiographs of the spine. Anterior or posterior wedging of vertebral bodies may be demonstrated on lateral radiographs of the spine and indicate the presence of previous vertebral fractures. Irregularity of the vertebral end plates often indicates the presence, or recent presence, of infection affecting the intervertebral discs; mycobacterial infection must be excluded in patients with irregularity of the vertebral end plates across multiple levels of the spine (Fig. 2). Absence or loss of distinction of one or more pedicles or spinous processes may indicate the presence of a tumour (Figs 3 and 4). An increase in the distance between pedicles of a single vertebra (increased interpedicular distance) across one or more spinal levels indicates the presence of intraspinal pathology, such as spinal dysraphism or neoplasm (Fig. 5). Radiographs of the spine obtained in an oblique orientation may be required if a suspected pars defect is not identified on radiographs performed in the lateral plane. In patients with suspected spinal instability, AP and standing lateral flexion-extension radiographs should be obtained (Fig. 6). Adequate imaging of the pelvis is also necessary, as pathological lesions arising from or involving the pelvis may manifest primarily as lower back pain.
Standing PA and lateral radiographs of the whole spine obtained using long 36-inch films are the standard way of imaging the bony anatomy of the whole thoracic and lumbar spine including the superior aspect of the pelvis to enable an accurate assessment of spinal alignment in both the frontal (coronal) and lateral (sagittal) planes and to apply validated measurement techniques. Following plain radiography, the imaging modality that is best suited for the further investigation of back pain in children and adolescents depends upon the pathology that is suspected on the basis of evidence obtained from prior history, examination and initial investigations.
Bone scintigraphy. In patients with persistent back pain, no abnormal findings on neurological examination, and normal plain radiographs, a technetium TC 99 m bone scan is the next most appropriate imaging modality to obtain to investigate for any underlying pathology. Technetium scintigraphy has significantly greater sensitivity, although not specificity, in detecting pathological bone lesions compared to plain radiography. Technetium scintigraphy should be utilised as a screening tool to identify regions of suspected abnormality, in patients in whom conditions such as discitis, vertebral neoplasms, and occult or stress fractures are suspected (Figs 3 and 7). A focused CT or MRI scan of the abnormal region can then be performed to better delineate the lesion and establish an accurate diagnosis. Bone scintigraphy performed in conjunction with CT, termed SPECT (single photon emission CT), has led to improved diagnosis of bone pathology, especially in detecting stress fractures in the pars interarticularis [32, 33].
Computed Tomography and Magnetic Resonance Imaging. CT is the most appropriate imaging test for further defining bone lesions in patients in whom a bony pathology has been identified by previous plain radiographs of the spine or bone scintigraphy (Fig. 3). Although CT scanning offers high diagnostic value, its use should be kept rationalised and restricted as repeated CT scanning may increase the incidence of malignant neoplasms in children [34]. MRI is the most appropriate imaging investigation for suspected soft tissue pathology and should be performed for children with abnormalities identified on clinical neurological examination, as MRI scanning effectively defines the spinal cord and neural canal (Figs 3 and 5). MRI is the optimal imaging modality to investigate the neural axis and exclude the presence of intraspinal pathology including spinal dysraphia, neoplasia, intervertebral disc herniations, slipped vertebral apophyses, and discitis. Spinal MRI should also be performed for paediatric and adolescent patients with atypical scoliosis that is also associated with significant back pain; investigations need to be performed to exclude spinal dysraphism in these patients (Fig. 8), and also in patients with spinal trauma associated with onset of demonstrable neurological abnormalities.
MRI results should be reviewed cautiously to prevent over-interpretation of findings, especially if disc degeneration is demonstrated. Tertti et al. [35] identified that 38% of adolescents with back pain and 26% of asymptomatic individuals had MRI findings consistent with disc degeneration by the age of 15 years.
Laboratory tests
Routine laboratory investigations are usually not required in the investigation of children with back pain. However, laboratory tests are extremely valuable in the investigation of paediatric and adolescent patients with back pain for which an underlying infectious, neoplastic, or inflammatory aetiology is suspected. For these patients, the initial investigations should include full blood count (FBC) with differential cell counts, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Raised ESR, leucocytosis, and anaemia in a paediatric or adolescent patient with fever and general malaise may be indicative of an infection, inflammatory arthritis, leukaemia, or lymphoma. Both CRP and ESR are valuable non-specific markers of both inflammatory and infectious disease processes. Nearly 90% of children with juvenile ankylosing spondylitis, are HLA-B27 positive; such patients also test negative for both rheumatoid factors (RF) and serum antinuclear antibodies (ANA), though other biochemical markers and mediators also influence the development of disease.
Impact of lifestyle, sport and exercise
As well as genetic, environmental and psychosocial influences, the lifestyle of children and adolescents also has a significant impact on the development and progression of back pain in patients of this age. Back pain is more commonly reported in adolescents who have hyperlordosis of the lumbar spine and in those with abnormal posture, including rigid thoracic kyphosis, tight hamstrings or upper back musculature, or abdominal musculature weakness [21]. Abnormal posture can be either structural or non-structural, and can develop due to cultural factors, lifestyle habits, inappropriate furniture, or inadequate seating.
The effect of exercise and sporting participation on back pain is complex and depends upon the level and intensity of activity, nature of the sport, and the incidence of any spinal trauma. Both high and low (less than two hours each week) levels of physical activity are associated with the presence of lower back pain [2, 36, 37], although variation exists in each individual’s susceptibility and tolerance to the effects of different levels of physical activity on back pain [38]. The activities and sports that are particularly associated with the development of back pain include volleyball, bodybuilding, aerobics, wrestling, gymnastics, fast bowling, football, tennis and cycling. However, the incidence of spinal injuries is more commonly associated with dancing, gymnastics, contact sports, and high intensity or excessive training. Limited physical activity secondary to excessive television watching or computer use also increases the risk of developing of back pain [38, 39, 40].
The school environment can also affect the development of back pain in children and adolescents; the duration of school lessons correlates with the onset of back pain, indicating that exercise and physical activity during lessons should be encouraged. Evidence from randomised controlled trials of school-based back care programs support this approach [41]. Adequate classroom furniture, especially seating, is important in the prevention of back pain; use of a seat wedge was shown to be effective in reducing the intensity and frequency of back pain in children [42].
Non-specific back pain
Children and adolescents with recent-onset back pain or intermittent back pain, associated with no ‘red flag’ symptoms (night pain, fever, weight loss, neurologic symptoms, self-imposed activity limitation, or persistent pain lasting greater than one month), and a normal physical examination may initially be managed for non-specific back pain. These patients may be recommended activity modification, home-based exercises, simple analgesia as required (paracetamol or non-steriodal anti-inflammatory drugs), and offered physiotherapy. Exercises and physiotherapy should focus on improving core strength and hamstring flexibility [43]. Evidence from randomised controlled trials indicates that children and adolescents with non-specific back pain experience improvement in intensity and prevalence of back pain following involvement in an eight-week school-based exercise program [44, 45]. Manipulative therapy does not reduce the episodes of back pain in children and adolescents [46]. Studies have suggested school bags not exceed 10–15% of a child’s body weight, though no definitive evidence exists regarding the influence of weight of school bags and the incidence of back pain in children and adolescents [47].
Children and adolescents presenting with back pain and initially managed for non-specific back pain should be have a full clinical assessment and review in approximately 3 months after initial assessment. If the patient has clinically improved, then they may continue with their current treatment regimen until their symptoms resolve. If the patient has experienced no clinical improvement, then further investigations should be initiated including full blood count, CRP, ESR, and PA and lateral radiographs of the spine, and re-assessment performed for an underlying cause of back pain.
Scheuermann’s disease
Epidemiology. In 1920, Scheuermann [48] provided the first description of a rigid kyphosis of the thoracic or thoracolumbar spine. Now termed Scheuermann’s disease, rigid thoracic or thoracolumbar kyphosis is the most common cause of structural kyphosis and thoracic back pain in adolescents. Scheuermann’s disease is the second most common etiological factor causing back pain in children and adolescents; the most common causes are spondylolysis and spondylolisthesis [20, 29, 30, 31]. The incidence of Scheuermann’s disease has been reported as between 4% and 8% within the general population, although these estimates may underestimate the true incidence of the disease due to the diagnosis of Scheuermann’s disease either being missed or attributed to poor posture [49, 50]. There is no evidence of gender predominance for Scheuermann’s disease [50, 51, 52].
Pathogenesis. Scheuermann [48] suggested that thoracic or thoracolumbar kyphosis develops as a consequence of avascular necrosis of the vertebral ring apophysis. However, the ring apophysis does not primarily contribute to the longitudinal growth of the spine and a defect in its formation should not lead to wedging of the vertebrae.
A hereditary aspect to Scheuermann’s disease has previously been described [53, 54, 55]. Previous studies have proposed an autosomal dominant pattern of inheritance with incomplete penetrance and variable expression [54, 55, 56].
Anthropometric and hormonal studies have suggested that growth hormone hyperincretion occurs in patients with Scheuermann’s disease, implicating elevated growth hormone levels in the disease aetiology [57].
Histopathologic studies investigating Scheuer- mann’s disease have demonstrated disorganized enchondral ossification similar to that occurring in Blount’s disease, thinning or absence of vertebral end plates and physes, defective formation of collagen fibrils, altered proteoglycan content, and increased levels of mucopolysaccharide in the end plates of the affected vertebrae [58, 59]. It remains unclear whether these changes represent a primary phenomenon with possible etiological implications or if they are secondary adaptations to asymmetric mechanical loading across the kyphotic segments. Thickening of the anterior longitudinal ligament across the levels of the kyphosis has been reported, as well as partial reversal of the vertebral wedging following bracing; these findings further supported a significant role for mechanical factors in the pathogenesis of Scheuermann’s disease [60, 61, 62, 63].
Clinical presentation. Scheuermann’s disease most commonly presents between late childhood and early adolescence with increasing thoracic or thoracolumbar structural kyphosis creating an acute gibbus, which deteriorates during the adolescent growth spurt and progresses until skeletal maturity. Poor posture is occasionally the primary symptom, in which case only mild pain co-exists; these features may result in delay in diagnosis as well as treatment. Pain associated with Scheuermann’s disease is usually reported as a non-radiating dull ache, which is well localized to the apex of the deformity at the midscapular region. The pain may be aggravated by prolonged periods of standing, sitting, or physical activity. The aching symptoms often subside as the end of skeletal growth approaches. In certain cases, low back pain may also be present as a consequence of the development of spondylolysis and spondylolisthesis; patients with Scheuermann’s disease have a greater incidence of spondylolysis and spondylolisthesis [64].
The normal thoracic kyphosis is generally accepted to vary between 20
The clinical examination of a patient with Scheuermann’s disease will demonstrate an exaggerated and rigid thoracic or thoracolumbar kyphosis with significant angulation on performing the forward-bending test and limited correction of deformity on performing hyperextension of the trunk. Patients may also develop a compensatory hyperlordosis in both the cervical and lumbar spine with consequent anterior protrusion of the head, in addition to tightness of the anterior shoulder girdle due to the thoracic kyphosis, and tightness of the hamstrings and iliopsoas, as the result of the increased lumbar lordosis. An associated structural scoliosis may be present in approximately one third of patients with Scheuermann’s disease [50]. Examination of the neurological system usually demonstrates no abnormalities. The lumbar spine and lumbosacral junction should also be routinely examined to investigate for the presence of associated spondylolysis and spondylolisthesis.
Imaging findings. A diagnosis of Scheuermann’s disease can be confirmed by plain radiography of the spine. The criteria described by Sorensen [53] include greater than 5
Natural history. Significant kyphosis or pain in adolescence is not a certain indication of impending disability into adulthood and should not be considered as an indication to begin treatment. Scheuermann’s disease is generally considered to be a benign condition resulting in little deformity and minimal symptomatology with the majority of symptoms resolving by skeletal maturity. However, for patients with a severe kyphosis associated with Scheuermann’s disease (
Recently, a natural history and long-term follow-up study demonstrated that patients with Scheuermann’s kyphosis adapted effectively to their condition and experienced minimal functional restrictions [52]. Despite patients with Scheuermann’s kyphosis reporting more severe back pain and a trend towards employment that did not involve heavy physical labour, there were no significant differences in self-reported days absent from employment due to back pain or requirement levels of analgesia, and patients were able to perform recreational activities at a similar intensity to control subjects. As well as achieving similar employment prospects to unaffected persons, adults with Scheuermann’s kyphosis attain equivalent levels of education and marriage, and it has also been demonstrated that patients’ satisfaction regarding cosmetic appearance improves with advancing age [71].
Scheuermann’s disease does not generally affect patients’ pulmonary function; adult patients whose kyphosis measures less than 100
Treatment. The timing and nature of treatment depends upon the severity of the kyphotic deformity, the presence of back pain, and the age of the patient. The majority of patients are treated non-operatively. Adolescents with a kyphotic deformity of less than 60
Physiotherapy for adolescent patients with Scheuermann’s disease may include hamstrings stretching, trunk extensor strengthening, and core stability exercises. Physiotherapy does not affect the natural progression of the kyphotic deformity, but is often beneficial for symptomatic patients with short flexible kyphotic deformities and as an adjunct to bracing therapy to minimise stiffness of the spine. Indeed, following a program of physiotherapy, pain levels in patients has been demonstrated to lessen by approximately 16–32% [73].
Bracing may improve the kyphotic deformity while the patient continues to grow and the kyphosis is still flexible [63]. It may be considered for adolescent patients whose kyphotic deformity is more than 60
Surgery in adolescents with Scheuermann’s disease should be considered only if there is a progressively severe deformity (
The biomechanical principles of surgical correction of kyphosis in Scheuermann’s disease include lengthening of the anterior concavity and shortening of the posterior convexity of the deformity. Successful outcomes have been described following either entirely posterior procedures (posterior compression instrumentation and arthrodesis), or combined anterior spinal release and interbody arthrodesis followed by posterior instrumentation and arthrodesis [75, 76]. For patients with significant remaining skeletal growth, instrumented posterior fusion only may be sufficient due to the remaining potential for significant anterior vertebral growth, which then provides additional anterior column stability. For patients with severe and rigid deformities that extend across only a few vertebral levels and cause an acute angular deformity, an additional anterior surgical release can be important.
A 17-year old patient who presented with persistent low thoracic back pain and a severe thoracic Scheuermann kyphosis with no associated scoliosis or spondylolisthesis (A, C). The patient underwent a posterior spinal fusion with apical segmental closing wedge osteotomies that produced an excellent outcome (B, D).
A dual rod construct with fixation incorporating several segmental pedicle hooks in a ‘claw’ configuration or multi-level bilateral pedicle screws is the preferred strategy for posterior instrumentation (Fig. 9). The posterior instrumentation and arthrodesis should always extend from the upper vertebral level of the kyphosis to include the first lordotic vertebral segment distally. The major complication associated with surgical correction of Scheuermann’s disease is the development of a junctional deformity, which may develop either above or below the primary kyphotic deformity if the spinal instrumentation and fusion are short relative to the deformity. Excessive correction of the primary deformity (
Lumbar Scheuermann’s: this is a separate disease compared to true Scheuermann’s disease. Lumbar Scheuermann’s may occur in male adolescents involved in intensive physical exercise (such as weight-lifting or heavy labour) and is thought to be a consequence of repeated trauma to the lumbar spine [77]. The classic type of lumbar Scheuermann’s affects three or more consecutive wedged vertebrae, whereas the atypical form affects only one or two vertebrae, and is associated with the presence of Schmorl’s nodes, and disc space narrowing [78]. Conservative management is recommended for lumbar Scheuermann’s, comprising activity modification and a lower back exercise program.
Epidemiology. Spondylolysis and spondylolisthesis are the most common causes of back pain in children. Spondylolysis is described as a unilateral or bilateral defect in the pars interarticularis, occurs in 6% of the general population, and usually affects the fourth or fifth lumbar vertebrae [79]. Spondylolisthesis may develop in the presence of bilateral pars defects and refers to the anterior translation of one vertebra relative to the next caudal segment. Spondylolysis most commonly appears after infants reach walking age and not in the newborn, suggesting that an upright posture associated with bipedalism may contribute to its development; there are also no known cases in non-ambulatory patients [80]. The prevalence of the condition is increased in children and adolescents who undertake strenuous physical activities that involve repetitive hyperextension of the lower spine. Such activities include gymnastics, weight lifting, football, swimming, and dancing. Teitz [81] reported a 15–20% incidence of spondylolysis in dancers who experience back pain. Jackson et al. [82] reported an incidence of 11% of spondylolysis in a cohort of young gymnasts. Rossi et al. [83] described an incidence of 43% of spondylolysis in divers and 30% in wrestlers. Repetitive exaggeration of lumbar lordosis during these activities is the primary predisposing factor causing increased stress across the pars interarticularis that may lead to a fatigue fracture.
Spondylolysis can occur secondary to Scheuermann’s disease where the compensatory lumbar hyperlordosis can contribute to an increased mechanical stress across the region of the pars. Evidence also exists for a heritable predisposition, with increased incidence amongst relatives, and an association of spondylolysis with spina bifida occulta [80, 84, 85, 86]. Spondylolysis is more common in males than females; however, progression is more likely in females than males [87, 88]. Certain populations have a higher incidence of the condition, particularly Eskimos (13% in young patients; 54% in adults), and Alaskans (40% in adults) [89].
Plain AP radiograph of the spine and lateral of the lumbosacral junction (A, C) of a patient who was referred for evaluation of a scoliotic deformity and underestimated low back pain show an antalgic scoliosis due to significant muscle spasm secondary to a grade IV dysplastic spondylolisthesis. Note that the scoliosis was spontaneously corrected to an almost straight spine once the spondylolisthesis was stabilised with transvertebral screws from the sacrum through the body of L5 (B, D).
Plain AP and lateral radiographs of the lumbar spine (A, C) show bilateral isthmic spondylolysis at L5 with grade 1 lumbosacral spondylolisthesis and a mild antalgic scoliosis with no structural component. Posterolateral fusion in situ with autologous bone graft achieved stabilisation of the lumbosacral articulation and spontaneous correction of the scoliosis (B, D).
Pathogenesis. Spondylolysis occurs at the junction between the relative stability of the sacrum and the mobility of the lumbar segments. Therefore, the most commonly affected level is the lumbosacral joint, which is anatomically unique in that the inferior articular processes of L5 face anteriorly and articulate with the sacral facets that are facing posteriorly, preventing the vertebral body of the L5 vertebra from translating anteriorly relative to the first sacral vertebra.
The orientation of the L5 vertebra to the sacrum, along with an intact intervertebral disc and ligamentous complex confer static stability to the lumbosacral joint [90]. Dynamic stability during motion or mechanical loading depends upon the interaction of the neuromuscular system with the static stabilizers (osseous and ligamentous structures – intervertebral disc). Compression is resisted by the intervertebral disc and by the vertebral body. Shear is resisted by both the disc and posterior bony elements. The pars interarticularis represents the bony connection and is a biomechanically weak area between these two regions. Repetitive loading in flexion-extension increases the stresses and may cause a fatigue fracture within the pars. Disruption of the posterior elements, which function as a tension band, either by an isthmic fracture or due to congenital dysplasia leads to anterior translation of the anterior vertebral column resulting in spondylolisthesis.
Classification. Newman, Wiltse and colleagues [91, 92] classified spondylolisthesis as five basic types: (I) dysplastic due to a congenital dysplasia of the dome of the sacrum and deficiency of the sacral facets or the inferior facets of the L5 vertebra leading to the anterior translation of the L5 vertebra relative to the sacrum (Fig. 10), (II) isthmic secondary to a defect of the pars interarticularis (Figs 11 and 12), (III) degenerative due to chronic intersegmental instability, (IV) post-traumatic due to acute fractures of the posterior vertebral elements involving the pars region, and (V) pathologic due to erosion of the posterior vertebral elements from a localized or generalized bony lesion(s).
Plain lateral radiograph of the lumbosacral joint shows a grade IV isthmic spondylolysis-spondylolisthesis (A), which was partially corrected and stabilised with posterior instrumentation and iliac crest bone autograft (B).
According to the Wiltse classification system, dysplastic and isthmic spondylolisthesis can occur in both children and adolescents. Dysplastic spondylolisthesis is largely analogous to developmental dysplasia of the hip. Progression to increasing severity of translation depends upon the extent of bony dysplasia and external features including the patient’s age, growth, weight bearing, and muscle imbalance. Isthmic spondylolisthesis can be further subclassified, as follows: (IIA) the defect is secondary to a fatigue or stress fracture of the pars region, (IIB) the pars is elongated but intact, (IIC) an acute traumatic fracture of the pars interarticularis. Recently, a further type of spondylolisthesis (VI; postsurgical or iatrogenic) has been recognised in addition to the original classification and which describes spondylolisthesis developing in children with spasticity who have undergone laminectomy or rhizotomy, which creates localized mechanical instability and has been reported to have an incidence of 20% [93, 94].
Marchetti et al. [95] proposed a revised classification system for spondylolisthesis, which suggested that the dysplastic and isthmic forms of spondylolisthesis should be considered together as developmental. Subclassifications of developmental spondylolisthesis include high dysplastic and low dysplastic, which can occur in association with spondylolysis or elongation of the pars interarticularis.
Clinical presentation. Patients affected with spondylolysis or spondylolisthesis generally present in early adolescence complaining of mechanical central lower lumbar back pain following strenuous sports or activities or protracted standing. The lower lumbar back pain may be associated with radicular symptoms, and only infrequently with postural deformity, which is most commonly present with high degree spondylolisthesis. The severity of symptoms usually does not correlate directly with the severity of spondylolisthesis [96]. There may be a history of participation in sporting activities during which the pain was first experienced; this pain may be alleviated by the cessation of the particular activity. More rarely an acute traumatic incident, such as a tackle during playing rugby, may initiate the onset of symptoms. The pain is well localized; radiating pain is only rarely a feature in young patients. However, radicular symptoms can develop later with progression of the severity of translation, as can compromise of bowel and bladder function [97].
Hamstring tightness and the classic Phalen-Dickson sign, which refers to an abnormal gait pattern with both knees and hips in a flexed position, may be present in patients with spondylolisthesis regardless of the degree of vertebral translation [97]. Hamstring tightness has been described as a typical feature of the condition in 80% of affected patients [98].
During clinical examination, pain can be reproduced upon passive or active hyperextension of the spine. In patients with high degrees of spondylolisthesis, the position of the sacrum is often more vertical such that the pelvis appears more flexed with the child needing to flex their knees to be able to stand upright. For patients with spondylolisthesis, palpation of the posterior spinous processes may demonstrate a ‘step-off’ across the affected segments; for example, the spinous process of the L5 vertebra may be more prominently palpable compared that of the L4 vertebra as it has been separated from its vertebral body at the level of the pars defect. If a traumatic incident has caused the onset of the symptoms, there may be tenderness on palpation of the spinous process of the L5 vertebra, representing an acute fracture of the pars interarticularis.
Scoliosis may occur in association with spondylolisthesis; this may be either a separate diagnosis, or more commonly secondary to rotatory translation, hamstring muscle spasm, or an antalgic phenomenon caused by significant spasm in the trunk muscles in symptomatic patients with a reported incidence of up to 60% (Fig. 10) [99, 100]. In a cohort study by Seitsalo et al. [101], fusion of the spondylolisthesis resulted in improvement of the scoliosis in over half of their cohort of patients.
Defects of the pars interarticularis may occur at the L4 vertebral level and above, although this is infrequent (Fig. 13). The severity of spondylolisthesis at these higher levels is usually less than when the pars defect occurs at the L5 vertebra; however, spinal stenosis and neurological symptoms and signs can also develop.
Plain AP and lateral radiograph of the lumbar spine (A and B) of a patient who presented with mild back pain show bilateral L4 spondylolysis, grade I spondylolisthesis, and sacralisation of L5. The lytic defects and spondylolisthesis occurred at the last distal mobile segment of the lumbar spine.
Imaging. The diagnosis can be confirmed by obtaining postero-anterior (PA), lateral, and oblique radiographs. Bilateral pars defects are readily detectable on a lateral radiograph of the lumbosacral spine in most patients (Figs 11–13). A unilateral pars defect can be identified by inspection of the collar (broken neck) of the ‘Scotty dog’ on an oblique radiograph of the lumbosacral spine. For a unilateral defect, the opposite side may demonstrate sclerosis in the pars region. The upright lateral spot radiograph of the lumbosacral spine is the most useful projection to monitor for progression of the severity of the spondylolisthesis.
Diagnosis may be challenging prior to the development of a fracture in the pars region, as only an increased degree of sclerosis in the area of the pars may be evident [102]. In a patient suspected of having an acute pars fracture or an impending stress fracture, bone scintigraphy can be helpful. Single-photon emission computed tomography (SPECT) can better define the defect, especially for stress fractures, while also demonstrating the potential of the lesion to heal. CT imaging can also be of benefit for delineating spondylolytic defects, except for impending stress fractures. CT imaging may help differentiate a pars defect from other pathologic processes that are detected by bone scintigraphy such as an osteoid osteoma or osteoblastoma. CT imaging can accurately demonstrate the fracture morphology and displacement and facilitate pre-operative planning. MRI can demonstrate bone marrow oedema within the pars in patients with relatively recent onset of symptoms, but MRI is not routinely obtained during investigation for pars defects. However, Hollenberg et al. recently reported that MRI is reliable for the classification of pars lesions [103]. MRI should always be obtained for the investigation of nerve root compression if patients present with associated radicular symptoms or neurological deficits.
Meyerding’s classification system is most commonly used to grade the severity of spondylolisthesis [87]. According to the Meyerding system, translation is measured as the percentage of the anterior displacement of the inferior aspect of the L5 vertebral body in relation to the antero-posterior length of the superior border of the sacrum as viewed on a lateral radiograph of the lumbosacral spine. No translation is graded as 0, grade I represents translation of 0 to 25%, grade II represents translation of 25 to 50%, grade III refers to 50 to 75% translation, grade IV represents translation of 75 to 100%, and grade V refers to greater than 100% translation (termed spondyloptosis). Translation greater than 50% (grade III to IV) is considered high-grade spondylolisthesis. Beutler et al. [104] recently suggested spondylolisthesis to be prognosticated by whether the pars defect was unilateral or bilateral; the authors reported an 82% incidence of vertebral translation when the pars lesion was bilateral [104].
Treatment. Treatment of spondylolysis and spondylolisthesis depends upon the patient’s age and estimated remaining skeletal growth, the presence and severity of symptoms, and the degree of displacement. In patients with recent acute onset of symptoms, initial management is usually conservative, with activity modification, relative rest, and use of NSAIDs. However, NSAIDs should be avoided in patients with early pars defects as NSAIDs can inhibit ossification, healing of the defect, and resolution of symptoms. If there is evidence of significant uptake on SPECT imaging, this signifies a high probability of healing of the pars defect with bracing and rest. Previous studies have reported that pars defects at the early stages, which show positive uptake on bone scintigraphy, have potential to heal with brace therapy, especially if the defect is unilateral [82, 105]. Morita et al. [105] have demonstrated, in patients with acute pars defects, that approximately 73% heal following bracing. In pars defects that are chronic, healing is less likely to occur with bracing and rest.
Bracing involves the application of a modified thoracolumbosacral orthosis (TLSO) to reduce the lumbar lordosis. This may be effective in alleviating symptoms in up to 80% of children with grade 0 or I spondylolisthesis [93, 106, 107]. Controversy exists regarding the required period of bracing; King [108] advocates a bracing period of up to 12 weeks, while other studies have suggested periods of bracing of up to 6 months [106, 107].
The aim of physiotherapy is to reduce the extension stresses acting across the lumbar spine. Physiotherapy therefore includes exercises to improve the flexibility and strength of hamstring, back (spinal extensor muscles and lumbodorsal fascia), and abdominal musculature [93]. Patients with grade 0 or I spondylolisthesis are allowed to resume their athletic activities once their symptoms have resolved. For patients with grade II spondylolisthesis, physical activities can be resumed, though specific activities causing hyperextension of the spine should be avoided [109].
The natural history of spondylolysis and spondylolisthesis is generally benign and most patients achieve satisfactory outcomes into adulthood with non-operative management. Progression of spondylolisthesis is not common for patients with less than 30% translation and rarely occurs after adolescence [79, 88, 110]. Beutler et al. [104] reported on asymptomatic patients with early diagnosis of spondylolysis and spondylolisthesis and follow-up over a 45-year period; they demonstrated that patients with pars defects followed a clinical course similar to that of the unaffected general population with marked slowing of progression of translation with each subsequent decade and no patients progressed beyond a 40% spondylolisthesis.
Spondylolytic defects can be treated surgically by direct repair of the pars defect. Patients who are most suitable for surgical repair of the pars defect include young patients with a spondylolysis located between the L1 and L4 vertebral segments and no associated spondylolisthesis. Surgical repair of pars defects of the L5 vertebra results in less predictable patient outcomes, probably because many spondylolytic defects of the L5 vertebra are the result of developmentally weakened and elongated pars. Several surgical techniques to repair the pars defect have been described, and all techniques involve debridement of the lytic defect and insertion of copious quantities of autologous iliac crest bone graft; stabilization of the free floating distal segment can then be performed using tension band fixation, a single screw, screw-hook, or combined screw-wiring compressive bony fixation [111, 112, 113, 114]. The authors’ preference is to perform compressive fixation across the spondylolytic segment using bilateral segmental pedicle screws and a contoured “U” shaped rod, which is positioned against the spinous process (Fig. 14). Features associated with a reduced rate of successful surgical repair of the pars defect include translation of greater than 2 mm across the pars defect and age of the patient of more than 30 years. The presence of associated intervertebral disc degeneration, as demonstrated on MRI, constitutes a relative contraindication to surgical repair of the pars defect; for these patients, fusion across the motion segment results in more favourable outcomes for the patient.
Plain AP and lateral radiographs of the lumbosacral spine (A and B) show repair of bilateral spondylolytic defects with the use of compression fixation (bilateral pedicle screws-rod) and bone grafting.
Surgical management for spondylolisthesis should be considered in growing children with translation greater than 50% (grade III and above) due to the high risk of subsequent progression, in patients with radiographic evidence of a progressive slip, or in those patients with persistent back pain not controlled by conservative measures. Patients with grade II spondylolisthesis are at risk for further progression and should be also considered for surgical fusion depending on the level of their symptoms. Posterolateral fusion (arthrodesis) in situ across one motion segment remains the mainstay of surgical treatment for children and adolescents with persistently symptomatic spondylolysis or grade I to II spondylolisthesis, and results in satisfactory long-term patient outcomes [98, 101, 115, 116, 117, 118].
The authors preferred surgical strategy is to use the Wiltse [119] bilateral lateral approach through a midline skin incision to perform an interfacetal-intertransverse fusion with the use of abundant quantities of autologous iliac crest bone graft (Fig. 11). If the spondylolisthesis is greater than 50%, it is recommended to extend the arthrodesis to the L4 vertebra, so that the fusion site is placed under compression. Following successful in situ arthrodesis, hamstring tightness usually settles in most patients within 12 to 18 months following surgery [90, 120]. However, previous studies have reported non-union and motion at the fusion mass when this surgical technique is used for to manage high-grade slips [98, 99, 121]. The subsequent progression of the severity of the spondylolisthesis is presumed to result from shear forces acting across the fusion mass in the presence of a high degree of lumbosacral kyphosis. Due to this difficulty, instrumentation techniques primarily incorporating the use of pedicle screws have been suggested to prevent further slippage of higher-grade spondylolistheses in young persons.
Symptoms of neural compromise associated with imaging results that demonstrate nerve root or thecal sac compression, mandate surgical spinal decompression. The segmental spinal instability following surgical spinal decompression will then need to be managed by posterior spinal fusion with transpedicular fixation.
Controversy exists regarding the need for reduction of spondylolisthesis at the time of surgical intervention, as the reduction itself carries the risk of iatrogenic nerve root injuries [122, 123]. Reduction manoeuvres are technically demanding procedures and are performed with the primary aim of correcting the lumbosacral sagittal imbalance and secondly also improving the translatory displacement in high-grade slips. Correction of lumbosacral kyphosis decreases the compensatory hyperlordosis above the level of the spondylolisthesis, thereby reducing the tensile forces across the fusion mass, while simultaneously providing a better cosmetic result. Reduction of spondylolisthesis is probably indicated in patients with high-grade slips associated with significant sagittal imbalance, or in those patients with neurological compromise requiring surgical decompression, which will probably itself to lead to further slip [122].
An alternative surgical technique to manage high-grade spondylolisthesis (grade III or above) with or without neurologic compromise is to perform posterior interbody fusion with the use of a fibular strut graft [124] or an S1 pedicle screw stabilizing the vertebral body of L5 to the sacrum, which is the authors’ preferred surgical strategy (Figs 10 and 12). Vertebrectomy of L5 followed by posterior screw fixation of the L4 vertebra to S1 is an additional technique that can be employed in extremely severe cases of spondyloptosis [125]; however, this procedure is associated with a high risk of neurological injury. Surgical experience and thorough understanding of the indications, limitations, and potential complications of each of these surgical techniques are required to achieve optimal surgical results and patient outcomes.
Aetiology-Pathogenesis. Discitis represents one end of a spectrum of infectious spondylitis that ranges from discitis to vertebral osteomyelitis with adjacent soft-tissue involvement and the development of abscesses. Discitis refers to a bacterial infection involving the disc space and adjacent vertebral end plates.
Discitis during childhood is rare, with an incidence of 1–2 per 30,000 [126]. It primarily affects infants, but may also occurs during adolescence [127]. The most common cause of discitis is the haematogenous seeding of bacteria originating from other anatomical sites of infection within the patient. Previous or concurrent infections such as otitis media, urinary or upper respiratory tract infections often form the nidus from which subsequent haematogenous spread occurs. It is proposed that pyogenic infections of the spine are caused by septic emboli entering the vertebral column through the nutrient arterial system [116]. This mechanism is very similar to the aetiopathogenesis of osteomyelitis in the metaphyseal region of long bones in children. Less commonly, discitis can develop following a traumatic incident or a surgical procedure (causing direct inoculation), or due to contiguous spread from an adjacent infected vertebra.
Unique anatomic features of the developing motion segment predispose the spine in children to discitis rather than vertebral osteomyelitis. In the growing child, the disc is located between the hyaline cartilage end plates of the cranial and caudal vertebral bodies. These cartilaginous end plates contain multiple blood vessels, which are important for nutrition of the immature intervertebral disc, but can also deliver blood-borne bacteria into the disc during episodes of bacteraemia [128]. Furthermore, the intervertebral disc in children is avascular and, therefore, bacteria may seed here and develop as a focus of infection where they are relatively protected from the patient’s immune system [117]. In contrast, the vascular anatomy of the vertebral bodies comprises a widespread network of intraosseous arterial anastomoses, which decrease significantly by 15 years of age, and disappears by adulthood. The intravertebral anastomoses form a collateral circulation that allow for eradication of bacteria and minimise the risk of pyogenic infection within the vertebral body [117].
Clinical presentation. The symptoms associated with discitis can vary and depend on the age of the child [3]. A history of preceding or concurrent illness or a traumatic incident may be present, and the duration of the symptoms can range widely. Back pain is a presenting symptom in only half of children with discitis [129]. Children less than 3 years of age are less likely to complain of back pain, but will instead present with a limp or difficulty or painful weight bearing resulting in the child being reluctant to mobilise. Young children may also present with being generally unwell, malaise, and non-specific fever. In children aged between 3 and 8 years, the main presenting complaints may again be unspecific, including vague abdominal or back pain, mild pyrexia, elevated blood white cell count identified on initial investigations, and reduced activity levels [130]. A diagnosis of discitis is often delayed due to the non-specific nature of the associated symptoms and the inability of young children to accurately localise or describe their pain. In comparison, adolescents will complain mostly of back pain, which is usually well localized in the lower thoracic, thoracolumbar, or lumbar spine. Adolescents with discitis may also develop an abnormal antalgic gait or posture, which is more prominent during spinal flexion (painful scoliosis). Adolescents may also describe pain radiating into the buttocks and legs due to nerve root irritation.
Clinical examination may demonstrate a low-grade fever; however, the majority of children do not present in an acutely ill state. Young children may refuse or be very reluctant to crawl or walk, and there will usually be focal tenderness on palpation of the spine at the level of the infection. There may be signs of an irritable hip but not to the extent that someone would consider septic arthritis. Paravertebral muscle spasm, limitation of spinal motion, and hamstring tightness are common findings. Stiffness of the spine with loss of lumbar lordosis can be noted when the child is standing or walking. Straight-leg-raising can be positive, but other abnormal neurological findings are usually absent. However, a complete neurologic examination should be routinely performed.
Investigations. Initial laboratory tests should include a complete blood count (CBC) with white cell differential counts, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), blood cultures during pyrexic episodes if the child is febrile, and a Mantoux test if tuberculosis is suspected [118]. The white blood cell count is often within the normal reference range or slightly elevated with mild leucocytosis [131]. The ESR will be moderately elevated due to the continuous infectious process, but has low sensitivity [132, 133, 134]. The CRP, which will also be elevated, can serve as an indicator to monitor the patient’s response to antibiotic therapy. Blood cultures are often negative. Repeated analysis of CBC, ESR and CRP are important to monitor the clinical course of the disease and response to antibiotic therapy.
Imaging studies need to include an AP and lateral plain radiograph of the spine. These may be normal at early stages of discitis. When the symptoms have been present for at least one week, the plain radiographs may demonstrate narrowing of the affected intervertebral disc space, and after 3 to 4 weeks of infection the radiographs may exhibit ‘saw-tooth’ erosions of the adjacent vertebral end plates [135, 136]. Chronic discitis can present with scalloping of the superior and inferior aspect of the vertebral body on plain radiographs [137]. Permanent loss of disc height or spontaneous disc space fusion can be seen with resolved infections.
For patients with persistent symptoms and clinical concern for infection with no changes on plain radiography, a technetium TC 99m-labelled bone scan is helpful in localizing any pathology. Bone scintigraphy changes may become apparent as early as 3 to 5 days following the onset of symptoms. In patients whose clinical features clearly indicate focal pathology affecting the spine, computed tomography (CT) scanning can be useful to define bony end plate erosion but does not significantly influence treatment decisions [138].
MRI is considered the most sensitive study to identify discitis because it defines the affected disc space, neural structures, and surrounding soft tissues, but also permits differentiation of isolated disc involvement from vertebral osteomyelitis, and epidural or paraspinal abscesses [139]. Early changes associated with discitis are best detected using T
The differential diagnosis for discitis includes neoplasia and metastatic tumours, including leukaemia (which usually affects the vertebral body rather than the disc and affects multiple vertebrae), osteoid osteoma and osteoblastoma (which commonly involve the posterior spinal elements), eosinophilic granuloma with characteristic flattening of the vertebral body (vertebral plana), pyogenic or tuberculous vertebral osteomyelitis, paraspinal or epidural abscess, septic arthritis of the sacroiliac joint in which pain can radiate to the lower lumbar spine, and Scheuermann’s disease, particularly if pain is localised in the thoracolumbar and lumbar spine.
Treatment: The most common organism causing discitis in children is Staphylococcus aureus [130, 131, 132, 143]. Therefore, management is empirical and targeted against S.aureus, usually using first generation cephalosporins administered initially intravenously until symptoms largely resolve and biochemical markers (CRP, ESR) drop towards their normal values [131, 144]. Following the period of parenteral administration, patients are usually converted to oral antibiotics for a further three to four weeks, with continued monitoring of inflammatory markers. Previously, it was believed that antibiotic therapy may not be necessary and that treatment by benign neglect combined with rest and immobilization would be adequate to achieve resolution of infection and symptoms. However, with an improved understanding of discitis it has now become apparent that withholding antibiotics is disadvantageous [1, 133, 137]. Nevertheless, rest and immobilization in a corset or underarm brace can contribute to healing, especially if the symptomatology has been chronic in nature.
Surgical debridement may be required if an established abscess has developed, the child is systemically unwell, or if there has been no significant response to antibiotic treatment. If surgical debridement is extensive, anterior bone grafting with use of either a rib or fibular strut graft in conjunction with spinal instrumentation may be necessary to restore stability to the vertebral column.
Vertebral osteomyelitis
Vertebral osteomyelitis represents a more advanced stage of infectious spondylitis than discitis. Vertebral osteomyelitis develops when bacteria progress from the intervertebral disc into the adjacent vertebral bodies. Vertebral osteomyelitis accounts for approximately 1% of all causes of pyogenic osteomyelitis [145, 146]. It tends to develop in infants and children between the ages of 2 weeks and 8 years, and is more common in the perinatal period [1].
Children who develop vertebral osteomyelitis commonly present with more advanced systemic symptoms and clinical signs compared to patients with discitis; these may include pyrexia, back pain, abdominal, chest, neck or flank pain, gait and postural disturbances (often with a marked limp), and significant tenderness and stiffness clinical examination of the spine [145]. Correa et al. [145] identified an incidence of 19% of associated neurological deficits, and a single patient experiencing permanent sequelae.
The findings on clinical examination will closely resemble those for discitis. Very young children may experience non-specific systemic symptoms and show signs of spinal rigidity and pain, and be inconsolable despite parental reassurance. Older children and adolescents can often describe more focal back pain, and also exhibit associated gait abnormalities.
Laboratory tests often show an elevated white cell count and a significant increase in the inflammatory markers (ESR and CRP). Changes on spinal radiographs may appear 2–6 weeks following the start of symptoms. Positive findings may develop on bone scintigraphy within one week after onset of symptoms. Blood cultures or bone aspiration biopsy samples may be positive in up to 80% of children with vertebral osteomyelitis, and the most common isolated organisms are Staphylococcus aureus or salmonella [145]. MRI is the most appropriate further imaging modality to investigate for extent of bony destruction, progression into the adjacent soft tissues, and any associated neurological compromise. In particular, the epidural space and psoas muscle should be carefully examined due to the high propensity for abscesses to develop in these anatomical sites [131, 146].
Management of vertebral osteomyelitis should follow similar principles to those for discitis; however, for vertebral osteomyelitis, the required duration of antibiotic therapy is usually longer, extending to at least 6 weeks [145, 147].
Tuberculous spondylitis
Tuberculous spondylitis refers to spinal osteomyelitis caused by mycobacterium tuberculosis, and is a common condition in developing countries (Fig. 2). Tuberculosis has recently again become a disease of heightened significance in developed countries due to the increasing levels of immigration from developing world populations. There is an increased prevalence of tuberculosis amongst immigrant populations, and also amongst immunosuppressed individuals [148, 149, 150]. Tuberculous spondylitis develops through spread of disease through haematogenous or lymphatic systems in patients in whom the primary focus of infection may be either the respiratory or genitourinary systems.
In children and adolescents, tuberculous spondylitis commonly occurs following primary pulmonary tuberculosis. The majority of paediatric patients that develop tuberculous spondylitis are affected before the age of 5 years [151]. In children, tuberculous spondylitis often presents with a long history of systemic malaise, loss of appetite and weight loss, nocturnal fevers, and chronic back pain. Such symptoms often exist for long durations before a diagnosis of tuberculosis is determined, and patients are often managed for the primary pulmonary infection initially. The gradual erosive nature of mycobacterium tuberculosis infections often results in delayed diagnosis and also secondary complications that are difficult to resolve. Back pain is often a later symptom during disease progression, and often only manifests after vertebral collapse has occurred. The thoracolumbar spine is the most commonly affected level of the spine and leads to development of a kyphotic deformity, though multiple vertebral levels are often affected.
Neurological compromise may develop either as the infectious process expands and narrows the spinal canal, or secondary to a progressive kyphotic deformity and compression of the spinal cord or cauda equina [149]. Paraplegia has been reported in up to 50% of paediatric patients affected by tuberculous spondylitis [151].
Laboratory investigations usually show an increased white cell count, increased ESR, and the CRP is often within the normal reference range [152]. The purified protein derivative (PPD) test will be positive with positive sputum or urine cultures depending on the site of the primary infection. MRI is the most accurate imaging modality to determine the extent of the disease and can be helpful for planning surgical debridement or decompression if required.
Treatment for tuberculous spondylitis requires combination therapy with a regimen of anti-tuberculous medication for a few weeks prior to surgical debridement with or without surgical decompression. Surgical debridement should be performed using an anterior approach to the vertebral column, unless urgent spinal decompression is required to treat paraplegia.
Painful scoliosis
The incidence of idiopathic scoliosis in children and adolescents is between 1–3%. Paediatric patients with idiopathic scoliosis present with concerns primarily relating to appearance and cosmesis. Despite the common belief that idiopathic scoliosis, unless extremely severe, is not associated with back pain, a recent report by Cushing et al. [126] identified that 23% of adolescent patients with mild idiopathic scoliosis experienced back pain; only 9% of the patients that had back pain in association with idiopathic scoliosis were eventually found to have another underlying pathology that could account for the back pain (including intraspinal anomalies, spondylolysis/spondylolisthesis, herniated disc, and Scheuermann’s kyphosis).
It is very important to acknowledge that painful scoliosis is a clinical finding and not a specific diagnosis in itself. Painful scoliosis can be caused by any of the conditions discussed in this review. A paediatric patient that has significant back pain with a previous diagnosis of scoliosis needs to be carefully re-evaluated with a detailed history and clinical examination, laboratory investigations and updated radiological studies. Another underlying aetiology should be suspected in the presence of stiffness of the lumbar spine related to muscle spasm, hamstring tightness, painful or restricted spinal range of movement, spinal tenderness, and gait or posture abnormalities. The presence of signs and symptoms of neurological compromise is the most helpful feature in distinguishing between idiopathic and non-idiopathic scoliosis.
Plain posteroanterior (PA) and lateral radiographs of the whole spine in the erect position should be obtained for paediatric patients with painful scoliosis. Focused or more localised views of the painful regions or the pelvis may also be required. In addition, MRI of the entire spine should be obtained in all children with painful scoliosis. Bone scintigraphy should also be considered to identify underlying causes for any painful scoliosis, such as spinal infections and tumours, stress fractures of the pars interarticularis, disc herniation, or congenital anomalies of the spinal cord. Laboratory investigations should also include complete blood count and inflammatory markers (CRP and ESR) to investigate for the presence of an infectious process. The definitive management of painful scoliosis will depend upon establishing a diagnosis for the underlying pathology.
Intervertebral disc herniation
Epidemiology. Intervertebral disc herniation has a much lower incidence in the paediatric population compared to the adult population; disc herniation in children and adolescents causes only 1–4% of all disc herniations [153]. The incidence of disc herniations in children and adolescents is approximately 0.2–3.2% and is often associated with spinal anomalies, spondylolisthesis, congenital spinal stenosis, transitional vertebra, sacralisation of the L5 vertebra, spina bifida occulta, lateral recess narrowing, and trauma [108, 137, 153, 154, 155, 156]. The most frequently affected spinal levels are the L4/L5 and L5/S1 segments. There may also be a history of disc herniations amongst close family relatives [2, 157, 158].
The incidence of disc herniation is higher in males than females, with a gender ratio of between 2:1 and 3:1 [154, 159, 160, 161, 162]. Although the overall incidence is lower in females, they tend to develop disc herniations at a younger age than males, likely related to earlier maturation in female adolescents.
Clinical presentation. As the symptoms of disc herniation may be intermittent in children and adolescents, the diagnosis can be difficult to achieve. Diagnosis of disc herniation is therefore often delayed, and only made after exclusion of other pathologies. Paediatric patients usually present with back discomfort and trunk rigidity, either with or without radicular neurological symptoms [153, 163, 164, 165, 166]. Symptoms of back pain are often exacerbated by prolonged sitting or standing, or by either coughing or sneezing. A history of a traumatic incident is often offered as the initiating event in approximately 50% of children [153].
Clinical examination of children with disc herniation often reveals limited neurological findings. Nevertheless, straight and cross-leg raising tests are usually positive. Motor deficits, and urinary or anal sphincter dysfunction are also infrequent [167]. Spinal examination usually reveals stiffness with limited movement, particularly of the lumbar spine on flexion, and tenderness localised to the lower lumbar spine adjacent to the disc herniation with loss of lumbar lordosis. Scoliosis can be present with significant trunk shift due to paraspinal muscle spasm but no evidence of vertebral rotation (Fig. 15).
Clinical photograph (A) of an adolescent patient who presented with left antalgic scoliosis, low back pain and left radiculopathy. CT scan (B) showed a large L5-S1 left disc prolapse, which was irritating the left L5 nerve root in the exiting foramen.
Investigations. Plain spinal radiographs may demonstrate a deformity in either the coronal or sagittal plane due to muscle spasm asymmetry (Fig. 15). Radiographs may also demonstrate congenital narrowing of the spinal canal with reduced interpedicular distance at the level of the stenosis or reduced intervertebral disc height. MRI is the best imaging to delineate the underlying pathology [168]. CT myelography can also be used to distinguish between a disc herniation and a traumatic slipped vertebral apophysis with posterior bony displacement in the spinal canal. Further differential diagnoses include spinal infections, spinal tumours, spondylolysis, spondylolisthesis, and spinal cord tethering [169].
Treatment. Patients with disc herniation should initially be offered a period of conservative management comprising relative rest, NSAIDs, and muscle relaxants, followed then by increasing mobilisation and prolonged limitation of activities, with use of an underarm brace if required. In some circumstances, an epidural injection of steroids can be helpful in relieving symptoms. However, this has not been tested specifically in children, and the balance between risk and benefit remains undetermined.
Non-surgical therapy fails to improve symptoms in 60–75% of affected children and adolescents, in which cases operative intervention should be considered [162, 163]. Furthermore, conservative management may often be beneficial initially, but gradually lose efficacy as the child continues athletic activities. The indications for operative intervention for disc herniation in children and adolescents include failure of conservative interventions, and significant or progressive neurological compromise. Following surgical excision of disc herniation, approximately 90% of children and adolescents report good or excellent outcomes [163].
The spondylarthropathies are a group of conditions affecting the axial spine and/or the peripheral joints that have a common genetic predisposition associated with expression of the HLA-B27 gene. Ankylosing spondylitis is the most common cause of these conditions and has a prevalence of approximately 0.2–1.2% in Caucasian populations [170]. Ankylosing spondylitis usually becomes symptomatic during the adolescent years and typically presents with lumbar back pain and early morning back stiffness, which is alleviated with movement and worsened with rest. Clinical diagnostic criteria do exist, and MRI may typically exhibit sacroilitis [171, 172]. Symptoms associated with ankylosing spondylitis often improve with NSAIDs, though tumour necrosis factor (TNF) inhibitors can also be effective for management of symptoms.
Fractures of the spine
Severe trauma is the most common cause of spinal fractures in children and adolescents, usually involving motor vehicle accidents, significant falls, athletic activities, or non-accidental injury (Fig. 6). Such trauma is most frequent amongst children aged less than 5 years of age or older than 10 years of age [173, 174]. For spinal fractures in children, the most commonly involved regions include the thoracic and lumbar spine, which are affected in 26–75% of patients [173, 175]. Approximately 20% of children with a spinal fracture will have signs or symptoms of neurological compromise on presentation [176].
Spinal injuries affecting paediatric patients differ in their pattern to those affecting the adult population, and some injuries are specific to the paediatric population. This is a result of the paediatric spine having greater soft-tissue elasticity and the unique ability for spinal bone remodelling during remaining growth. Spinal injuries that are exclusive to children and adolescents include spinal cord injury without radiographic abnormalities (SCIWORA), slipped vertebral apophysis, and spinal trauma due to child abuse.
Spinal cord injury without radiographic abnormality (SCIWORA)
Spinal cord injury without radiographic abnormality (SCIWORA) is defined as spinal cord injury, which is usually complete, without radiographic evidence of vertebral fracture or dislocation. SCIWORA has an incidence of 16–19% amongst all spinal cord trauma in paediatric patients [174, 177, 178, 179, 180]. In contrast, SCIWORA is very infrequent amongst adults, with an incidence of 2 per 1000 [181]. Carreon et al. [182] reported that SCIWORA has an incidence of 11% in children under the age of 9 years, and suggested that the lower incidence reported in their study compared to previous studies was due to the increased sensitivity of modern imaging modalities [182]. The vast majority of spinal lesions affect a single area of the vertebral column and usually involve the upper thoracic and cervical spine. Most patients with SCIWORA exhibit neurological symptoms immediately following the traumatic incident; in some patients there may be a delay between the traumatic incident and onset of neurologic dysfunction of up to 4 days [183].
Etiological factors contributing to the development of SCIWORA include neural cord traction or rupture, traumatic infarction, and disruption of the vascular supply to the spinal cord following an aortic injury in children that have sustained blunt abdominal trauma. The pathophysiology underlying SCIWORA in children involves the neural structures being vulnerable to injuries caused by severe longitudinal traction, excessive flexion or extension, or forced rotation, particularly in the absence of rigid protection conferred by the immature bony structures, and despite the increased flexibility of the spinal column in children [184].
MRI can now provide accurate diagnosis of SCIWORA and identify an acute haemorrhage or oedema affecting the spinal cord. Management of SCIWORA comprises immobilisation of the spine and treatment with steroid medication. Surgical decompression might be indicated if either a defined lesion or progressive neurological deficit is present.
Slipped vertebral apophysis (limbus fractures)
Slipped vertebral apophysis (also known as limbus fractures) refers to an avulsion of an osseous fragment from the posterior rim of the vertebral body in association with a central intervertebral disc herniation. The line of the fracture travels through the hypertrophic region of the vertebral growth plate. Limbus fractures develop due to repeated micro-trauma; this detaches the apophyseal ring from the vertebral body at its weakest point at the osteocartilaginous junction. These injuries are usually a consequence of severe traumatic flexion and rotational forces. Limbus fracture usually occur in adolescent patients, and twice as frequently in males compared to females [185].
Takata et al. [186] classified limbus fractures into three types; Epstein et al. [187] subsequently added a fourth type to this system. Type I fractures only affect the cartilage of the posterior vertebral margin; type II fractures include larger central avulsion of the cortical and cancellous osseous rim; type III fractures involve more lateral tear drop fractures; and type IV fractures involve the whole length and breadth of the posterior vertebral body.
The majority of limbus fractures arise in the lumbar spine and can provide a difficult diagnostic challenge as the clinical symptoms and signs often resemble those of an intervertebral disc herniation. Plain radiographs may demonstrate the limbus fracture, but CT scanning is often required to identify in detail the morphology of the osseous fragment if surgical intervention is being considered.
Spinal trauma in child abuse
The incidence of spinal fractures occurring from child abuse has been reported to as high as 3% [188, 189, 190]. It is also estimated that 3–8% of spinal injuries in paediatric patients are due to child abuse [191]. A high level of concern regarding non-accidental injury or child abuse must always be maintained for children sustaining injuries with an absent or inconsistent history of trauma, multiple skeletal fractures at different stages of healing, or a young child with a recent or sudden onset of spinal cord dysfunction, which may be an atypical form of ‘shaken baby syndrome’.
Physical abuse in children usually results in vertebral body fractures with anterior wedging leading to a kyphotic deformity, impaction of the vertebral endplates, compression of the intervertebral discs, or subluxation of dislocation of the spinal column [176]. Subtle symptoms are usually present, but neurological compromise may occur [192]. Plain radiographs should be performed to obtain a full skeletal survey, including lateral whole spine radiographs, which may reveal other fractures or injuries of different ages that may facilitate establishing the diagnosis.
Neoplasms
Tumour should always be excluded from the differential diagnosis during investigations for children and adolescent patients presenting with back pain. Tumours are not an infrequent cause of back pain in young patients [20, 31]; these may be due to primary or metastatic involvement of the spinal column or spinal cord. For patients greater than 21 years of age, most tumours affecting the spine will be malignant in nature; for patients less than 21 years of age the majority of tumours affecting the spine will be benign neoplasms. Children are rarely affected by malignant primary tumours of the spine; less than 30% of all primary osseous tumours in paediatric patients are malignant, and an even lower proportion involve the spinal column [193].
Pain is the main presenting complaint in children affected by tumours involving the spine. Symptoms are often vague and non-specific, which may cause a delay in establishing the diagnosis. Weinstein et al. [137] identified that 93% of children with an underlying diagnosis of a spinal tumour reported pain as the main symptom. Pain associated with an underlying spinal tumour tends to be progressive and unremitting, unrelated to activity level, unrelieved by rest, and often exacerbated at night. If a spinal tumour is suspected and associated with neurological dysfunction, urgent investigation, diagnosis, and treatment are required. A high level of concern for an underlying neoplastic disease should be maintained in patients with a painful scoliosis, focal tenderness on spinal palpation, or a palpable mass on examination (Fig. 4). The interval from initial presentation by the child or adolescent patient to establishing a diagnosis can be protracted due to the varied and diverse clinical signs and symptomatology that may be associated with spinal neoplastic disease [194].
Benign neoplasms
Osteoid osteoma
Epidemiology. The clinical pathology of osteoid osteoma was initially described by Jaffe in 1953 as a focal core of bone encompassed by fibrovascular tissue with a sclerotic margin [195]. Osteoid osteoma accounts for 1% of spinal neoplasms and 11% of all primary osseous tumours in patients aged 10–25 years [196, 197]. Ten percent of osteoid osteomas involve the spine. The incidence of osteoid osteoma is particularly high in children and adolescents aged 6–17 years, with a male to female predominance of 2:1 [198]. Osteoid osteoma usually arises in the posterior osseous elements of vertebrae with the pedicle and lamina most frequently involved. It may also affect the transverse processes or the facet joints (Fig. 7). Osteoid osteomas also most commonly affect the lumbar spine (
Clinical presentation and investigations. The most common presenting symptom associated with an underlying osteoid osteoma is back pain, which is most severe at night and may be relieved by NSAIDs. A non-structural scoliosis may be present due to paraspinal muscle spasm, and the tumour often arises within the apex and the concavity of the deformity.
Plain radiographs may show a radiolucent zone encompassed by a sclerotic rim. Bone scintigraphy with Tc 99 m is the most sensitive imaging study to identify an osteoid osteoma. Definitive management by surgical debridement also offers effective resolution of back pain [199].
Osteoblastoma
Epidemiology and clinical presentation. Osteoblastomas are benign lesions that are associated with the same clinical features as osteoid osteomas, and also usually arise in the lamina or pedicle. Histopathologically, osteoblastomas are indistinguishable from osteoid osteomas, but are usually greater than 2 cm in diameter. Osteoblastomas account for 1% of primary benign tumours; over 40% of osteoblastomas affect the spine [196, 200]. These tumours are frequently found in the posterior elements of the spine and are both expansive and destructive. Patients with osteoblastomas have a high frequency of associated neurological dysfunction, which is found in 69% of patients, due to their relatively large size, expansion into the spinal canal, and potential to compress the spinal cord or nerve roots [201]. Saifuddin et al. [202] reported that 63% of patients with either an osteoid osteoma or an osteoblastoma developed a painful scoliosis, and the pathological lesion was located at the concavity of the curve in all patients.
Imaging. CT is the most appropriate imaging study to delineate the lesion and to facilitate pre-operative planning. MRI can also be useful to identify impingement of any neural structures if signs or symptoms of neurological dysfunction are present.
Treatment. The initial treatment for both osteoid osteomas and osteoblastomas should include a trial of NSAIDs. NSAIDs will usually be more effective in treating back pain due to osteoid osteoma compared to osteoblastoma. NSAID therapy should be reserved for osteoblastoma in which surgical excision would be associated with significant risk of neurological injury and permanent disability. Intralesional surgical procedures with resection of the entire focus of the osteoblastoma result in improvement in symptoms and are the preferred treatment for both osteoid osteoma and osteoblastoma. CT-guided ultrasonic ablation is another treatment option, but is associated with a spinal cord and nerve root injury complications [203].
Following excision of osteoid osteoma or osteoblastoma, tissue samples from the margins of the lesion need to be carefully assessed histologically to ensure complete excision of the neoplastic disease. If tissue examination indicates incomplete surgical excision of the tumour, recurrence of disease may occur in 10% of tumours [1]. The rate of disease recurrence is higher for the more aggressive forms of osteoblastoma [204]. Radiotherapy is not advised unless the lesion is inoperable or recurrent, as radiotherapy is associated with risks including myelitis and malignant transformation.
Improvement in painful scoliosis depends upon the duration of time from the onset of symptoms prior to excision. If the painful scoliosis was present for more than 15 months prior to resection, especially if due to an osteoblastoma, it is likely to progress into a structural scoliosis and to persist following surgical intervention [197].
Aneurysmal bone cyst (ABC)
Pathophysiology. Aneurysmal bone cysts (ABC) are expansile lytic lesions comprising a thin margin encompassing blood-filled cystic cavities. The term aneurysmal refers to its radiographic appearance. The underlying aetiology of ABC remains poorly understood, though they have a propensity to develop following a traumatic incident or from pre-existing osseous lesions including osteoblastoma or, less commonly, a malignant tumour such as an osteosarcoma. The pre-existing lesions may disturb the vascularity of the underlying bone and thereby lead to the development of an ABC.
Incidence. ABCs usually occur in younger patients (median age of incidence in 13 years) with no gender predominance [205]. It usually affects patients older than 5 years of age, though 85% of patients are younger than 20 years of age. Between 16–20% of ABCs develop in the vertebral column of the lumbar or cervical spine, and 20–40% affect more than one vertebral level [206, 207]. Two-thirds of ABCs affect the posterior elements and can infiltrate through the pedicles into the vertebral body anteriorly.
Clinical presentation & investigations. On initial presentation, most children and adolescents with an ABC report sudden onset of back pain. They may also experience spinal rigidity, especially in the lumbar region, with reduced range of movement and a painful scoliosis. Further clinical signs and symptoms may include a palpable swelling localised around the affected region of the spine, and neurological dysfunction.
Imaging. On plain radiographs, ABCs usually exhibit regions of cortical expansion with osteolytic zones containing septations that resemble a soap bubble appearance (Fig. 3). Erosion through bony cortices and invasion of adjacent soft tissues in not an infrequent finding – this can be best visualised by MRI that may also show fluid levels within the neoplastic tissue.
Treatment. Management of ABC comprises en bloc marginal resection of the tumour and curettage, which is associated with an increased risk of significant intraoperative bleeding. This can be ameliorated by use of preoperative selective arterial embolization, but this requires interventional radiologists experienced in this procedure to minimise the further risk of neurological compromise affecting the spinal cord. Embolization treatment itself can sometimes lead to resolution of an ABC. Instrumented spinal fusion might be necessary if surgical resection of an ABC leads to mechanical instability. Recurrence rates for ABC after incomplete disease resection can be as high as 25%.
Langerhans’ cell histiocytosis (eosiniphilic granuloma)
Langerhans cell histiocytosis (LCH) is a self- limiting neoplastic disease process, which is derived from the proliferation of lipid containing histiocytes from the reticulo-endothelial system within the vertebral body.
Eosinophilic granuloma (histiocytosis X) is a form of Langerhan cell histiocytosis that behaves as similar to an infection and a tumour, but is likely not a true neoplasm. It may develop across several vertebral levels and most commonly occurs before the age of 20 years. Children and adolescent patients with eosinophilic granuloma often present with significant pain localised to the region of the granuloma. Rarely, neurological dysfunction has developed prior to presentation, usually if the disease affects the cervical spine [208].
Imaging. Plain radiographs may demonstrate established vertebral collapse or flattening of the affected vertebra (‘vertebra plana’) [196]. In older children, wedge-shaped collapse of the vertebra may be evident. Biopsy of the lesion is necessary to exclude malignancy while establishing the diagnosis. Further skeletal survey radiographs should be obtained including the entire spinal column, limbs, and skull as the disease may be multifocal and because the disease is often undetectable by bone scintigraphy.
Treatment. Eosinophilic granuloma is usually managed conservatively as the disease is often self-limiting. The deformity in the vertebral body usually resolves with full restoration of vertebral height. The use of a brace can be helpful to prevent the development or progression of kyphosis as the vertebral body recovers. Patients who are found to have multifocal disease should be referred to the regional haematology/oncology service for consideration for treatment with corticosteroids or chemotherapy.
Malignant tumours
Ewing’s sarcoma
Ewing’s sarcoma is the most common malignant bone tumour in children and adolescents, with a peak incidence in children aged 5–15 years [209]. Between 3.5–5% of all Ewing’s sarcoma tumours develop in the spinal column; the pelvis is the most frequently affected site [210].
Symptoms. Patients with Ewing’s sarcoma usually present with complaints of back pain or neurological dysfunction; the latter is due to soft tissue invasion by the tumour and is related to the proximity of the lesion to the spinal cord or spinal nerve roots. Systemic malaise and fevers may also develop. Clinical examination may reveal a palpable mass and reveal any associated neurological compromise. Laboratory tests show an increased ESR, which can mislead towards an initial suspicion of an infective pathology. Radiographic studies will demonstrate erosion and collapse of the affected vertebral bodies (vertebra plana; requires careful investigation to differentiate from similar appearances of eosinophilic granuloma) with preservation of undisturbed disc spaces [211]. Ewing’s sarcoma is best diagnosed by biopsy of the adjacent soft-tissue mass.
Ewing’s sarcoma is generally associated with a poor prognosis because en bloc resection of the tumour is usually not feasible. Protocols combining radiation and chemotherapy can provide some short-term local relief of symptoms and should be considered as the initial treatment option to potentially make possible subsequent en bloc excision of the tumour. Ewing’s sarcoma often develop metastatic disease, most commonly affecting the spine, lungs, ribs, lymphathic system, brain, and abdominal organs.
Osteosarcoma
Osteosarcoma is the second most common primary malignant bone tumour after myeloma. Osteosarcoma infrequently affects the spine; less than 2% of all osteosarcomas involve the spinal column [212, 213]. The peak incidence of osteosarcoma is during adolescence, with 50% of osteosarcomas developing during the second decade of life, usually during the period of accelerated growth. The aetiopathogenesis of osteosarcoma remains poorly understood, though it may develop in relation to Paget’s disease of bone, radiation therapy, benign neoplastic disease, and retinoblastoma in paediatric patients.
A high degree of suspicion for an underlying malignant pathology should be maintained for any child presenting with unremitting back pain that persists for days to weeks. Neurological dysfunction is often evident on initial clinical assessment. Spinal radiographs will show a mixed osteolytic and sclerotic lesion affecting the vertebral body, and which must be differentiated from an osteoblastoma or ABC. The diagnosis of osteosarcoma can be confirmed histologically following CT-guided biopsy of the lesion. MRI is the most optimal imaging study to investigate for soft-tissue invasion by the tumour. CT imaging and bone scintigraphy must be performed to exclude any metastatic disease.
Treatment. The management of osteosarcoma should comprise preoperative chemotherapy with the aim to achieve primary tumour regression, thereby permitting en bloc surgical excision of the tumour. Post-operatively, multiple cycles of chemotherapy are required. Local radiotherapy may also be considered for neoplastic disease that is assessed as inoperable. The prognosis for young patients with osteosarcoma is generally poor, though recent advances in chemotherapy have lead to improved survival and patient outcomes.
Leukaemia
Leukaemia is the most common malignancy in childhood; 6% of children presenting with back pain as the primary complaint are found to have an underlying diagnosis of leukaemia. The clinical features are often non-specific and the diagnosis may be difficult to achieve, and therefore a high level of concern regarding an underlying malignant pathology must be maintained for children primarily presenting with persistent back pain. Laboratory blood tests provide more diagnostic information than spinal imaging (including radiographs and bone scans) if leukaemia is suspected. Flattening of several vertebrae at adjacent or non-contiguous levels is often seen in paediatric patients with leukaemia. Back pain is usually a result of the development of pathological fractures or gross expansion of the lesion within the vertebral column. Leukaemia is managed medically, the exact nature of which depends upon the type of leukaemia.
Conclusion
Clinical evaluation of children and adolescents presenting with back pain is challenging. It requires a clear and comprehensive clinical approach. Current evidence indicates that 10–30% of the normal young population experience non-specific back pain, which is generally benign and self-limiting. Spine pain in children and adolescents may also occur more frequently than previously recognised, and is often related to psychosocial factors. It is also important that all young patients seeking medical review for persistent back pain should be thoroughly investigated with a view to excluding underlying significant pathology. Employing modern imaging modalities, the physician possessing skilled clinical expertise and a high index of suspicion holds the key to a prompt and accurate diagnosis.
Footnotes
Acknowledgments
Mr SB Roberts, Mr K Calligeros, and Mr AI Tsirikos all designed, prepared and drafted the final manuscript.
Conflict of interest
No grants or external funding was received by the authors to support research and preparation of this manuscript. No payments or other benefits nor any commitment or agreement to provide such benefits were received from a commercial entity. Neither payment or direction, nor agreement for payment or direction, of any benefits to any research fund, foundation, educational institution or other charitable or non-profit organisation with which the authors are affiliated or associated were received from any commercial entity.
Appendix
Five databases (PubMed, ISI Web of Science, Embase, Cochrane Library, and BioMed Central) were searched from inception to April 2017 for the following initial search terms to identify potentially relevant articles for this narrative review: child, adolescent AND back pain, In addition, reference lists of relevant and included papers were searched to identify other potentially suitable articles. Criteria for inclusion of articles included the following: the patient cohort comprised children and/or adolescents; the article reviewed prevalence, incidence, aetiopathogenesis or clinical management of conditions associated with back pain, and the study was available in peer-reviewed English-language publication. Titles and abstracts of citations were reviewed for inclusion by the study authors, and full text articles subsequently retrieved. A flow diagram illustrating the review process for inclusion of articles for the narrative review is shown in Fig. 16.
Flow diagram illustrating the database search, review and selection of articles for inclusion in the narrative review.